I know that a lot of RPGers want to try them all, but If I join a jeep club, it's because I have a jeep I want that takes me to all those places out in the wild to enjoy the wild. It isn't to test drive every jeep model that comes up year-upon-year, or talk about how to get max horsepower out of the engine in a garage full of gearheads. So long as it gives me the experience I want, I'm not really looking to invest again because the 2020 has bluetooth and a cup warmer.
I know every inch of the one I've driven for decades, every vibration, and other feedback loops most don't even notice; and it never fails in getting me to that wild outdoors that's the real driver for my participation in the hobby.
Interesting take, but I am not sure that the jeep metaphor is entirely accurate.
A better metaphor for designing and running a campaign is putting together a collage. I think I saw Jeff Rients use this metaphor on his blog recently (so credit to him). You take a bunch of pieces, some of which you make, some of which you just cut out, then stick them together in a coherent fashion to make your own personalized thing to share with all of your goober friends (my friends are goobers, anyways). The rule system you use is a bit like the backing material and glue that hold everything together. They all essentially do the same thing, but different mediums can have wildly different effects on how the collage actually comes out.
Personally, experimenting with this 'backing material' has helped me becoming a much better DM, as well as refine my own tastes a bit.
One of the most salient things that I have learned is that you can't necessarily see how the largest differences between systems will manifest themselves without actually trying them. I didn't know what I didn't like about 5e until I went back and played DCC and 1e for a while. On the same token, I remember as a kid going from 2e to 3e and thinking that 3e was going to be god-awful, but it actually got rid of most of the issues I had (at the time) with 2e. I just had to get over the 'NEW THING BAD' feeling and actually try it.
Of course, now I view 3e as the worst of all systems but I wouldn't have been able to see that unless I tried 5e.
And my opinion of 5e has changed as I've experimented with different systems. 5 years ago, when I picked up the 5e starter box and got back into DMing, I would have said Race-As-Class was horrendously stupid, but now that I've actually used Race-As-Class, I really prefer it. Lots of aspects of different game systems are like that. They look unbelievably weird at first, but then once you try it and adapt, they feel considerably different than you thought they would.
Experimenting with new systems is also fun and entertaining because it forces the players to also think outside of their comfort zone, which can be a lot more engaging. Seeing my players do new and unexpected things is my favorite part of DMing. I still remember the first time I tried 1e with my group. One of the players decided to make a magic-user and at first said something like "this is bullshit, I only get one spell?" He spent a long time looking through the spell list to find the right one. Later, when they were in the dungeon, after running a way from a bunch of horrible monsters/traps, the party was ambushed by a group of Halflings. He then cast his single spell, which was Sleep, putting all of the Halflings to sleep. He then said "ok, I can just going to go cut their throats now," to which I replied "no, you can't do that." He then read the spell to me verbatim and I realized he was right. He gleefully moved his miniature around the battle mat proving he could make it to all of them before the effects of Sleep wore off. I laughed so hard I nearly cried because it was so unexpected and comical. Also, I think that player had fun looking through the spells, knowing he could only take one, and then deciding on Sleep, which is a spell he would have just skipped in his native 3.5e for a damage dealing spell. Being off balance and trying new things made that session more fun for both of us.
While you can kind of tweak your system to your liking, a lot of systems have considerable differences which you can't necessarily see until you try a different rule set and are a bit off-balance. Here in lies the crux for me. I am not advocating 'trying all of the newest ones,' I am just advocating getting out of your comfort-zone every once in a while. Try a one-shot of some weird system you've never used before. Try running the same dungeon you made in two different systems. You'll get better as a DM and you might even find a few less than obvious things you want to incorporate into your material that you write/your regular game. It's also pretty fun (in my opinion, of course.), though it might be slightly uncomfortable at first, like jumping into a pool of cold water.
Like any skill (DMing and making content are definitely skills), being outside of your comfort zone will make you view things differently and definitely improve your abilities overall. It has certainly helped me and it's been fun along the way!
That was more words than I intended.